Pressure cylinder with oil storing function

ABSTRACT

A pressure cylinder includes a first cylinder body having accommodated therein a piston. a second cylinder body defining therein a first passage vertically connected to the first cylinder body, an oil storage chamber vertically connected to the first passage, a second passage vertically connected to the oil storage chamber and a pressure chamber vertically connected to the second passage and having a cross-sectional area smaller than the oil storage chamber, and a piston rod inserted through the first passage of the second cylinder body in an airtight manner and having its one end connected to the piston and its other end movable by the piston between a first position in the oil storage chamber and a second position in the pressure chamber to add a pressure to the hydraulic oil in the pressure chamber and to let the hydraulic oil in the oil storage chamber be supplied to the pressure chamber to make up any hydraulic oil loss, maintaining the output.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a pressure cylinder and more particularly, to a pressure cylinder having an oil-storing function.

2. Description of the Related Art

Referring to FIG. 1, a conventional pressure cylinder 10 generally comprises an air cylinder 12 having a relatively larger cross section, a hydraulic cylinder 14 having a relatively smaller cross section and an oil storage tank 16 in communication with the hydraulic cylinder 14. The air cylinder 12 has a piston 122 set therein and a piston rod 124 connected with its one end to one side of the piston 122. The piston rod 124 is stopped between the hydraulic cylinder 14 and the air cylinder 12 to prohibit communication therebetween. The other end of the piston rod 124 is movable from the open end of the hydraulic cylinder 14 toward the inside of the hydraulic cylinder 14. The oil storage tank 16 is adapted for storing a hydraulic oil to make up the internal oil loss of the hydraulic cylinder 14, enabling the hydraulic cylinder 14 to be filled up with the hydraulic oil. As illustrated in FIG. 2, when applying an air pressure to force the piston 122 in moving the piston rod 124 into the inside of the hydraulic cylinder 14, the piston rod 124 blocks communication between the hydraulic cylinder 14 and the oil storage tank 16 and imparts a pressure to the hydraulic oil in the hydraulic cylinder 14, thus, the hydraulic cylinder 14 can output a hydraulic pressure greater than the applied air pressure.

However, due to the arrangement of the oil storage tank 16 in the pressure cylinder 10, the pressure cylinder 10 has a large size and a heavy weight. Further, as the hydraulic oil used has a high viscosity, it flows slowly. Further, as the hydraulic cylinder 14 and the oil storage tank 16 are kept apart at a distance, the oil supplying efficiency of the pressure cylinder 10 to supply the hydraulic oil to the hydraulic cylinder 14 may be insufficient, causing the hydraulic cylinder 14 unable to output the desired oil pressure.

Therefore, there is a room for improvement on the conventional pressure cylinder.

SUMMARY OF THE INVENTION

The present invention has been accomplished under the circumstances in view. It is the main object of the present invention to provide a pressure cylinder, which has a relatively smaller size and weight and achieves quick hydraulic oil refill to ensure a high stability of output.

To achieve this and other objects of the present invention, a pressure cylinder comprises a first cylinder body having accommodated therein a piston. a second cylinder body defining therein a first passage vertically connected to the first cylinder body, an oil storage chamber vertically connected to the first passage, a second passage vertically connected to the oil storage chamber and a pressure chamber vertically connected to the second passage and having a cross-sectional area smaller than the oil storage chamber, and a piston rod inserted through the first passage of the second cylinder body in an airtight manner and having its one end connected to the piston and its other end movable by the piston between a first position in the oil storage chamber and a second position in the pressure chamber.

Based on the aforesaid arrangement, no any spare oil tank is necessary to refill the pressure chamber with the necessary hydraulic oil, and therefore, when compared to the conventional pressure cylinder design of the same capacity, the pressure cylinder has a relatively smaller size and weight. Further, the second cylinder body is adapted for storing the hydraulic oil. When the fluid level of the hydraulic oil reaches the oil storage chamber, the pressure chamber is fully filled up by the hydraulic oil, at this time, the hydraulic oil in the pressure chamber is compressed when the piston rod is moved by the piston into the pressure chamber. Further, during the operation of the pressure cylinder, the hydraulic oil in the oil storage chamber is supplied to the pressure chamber of the second cylinder body to make up any hydraulic oil loss, maintaining the oil pressure output.

Other advantages and features of the present invention will be fully understood by reference to the following specification in conjunction with the accompanying drawings, in which like reference signs denote like components of structure.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic sectional view, illustrating an action of a conventional pressure cylinder.

FIG. 2 corresponds to FIG. 1, illustrating another action of the conventional pressure cylinder.

FIG. 3 is a schematic sectional view of a pressure cylinder in accordance with the present invention, illustrating a piston reached its upper limit position.

FIG. 4 is a schematic sectional view of the present invention, illustrating another operating status of the pressure cylinder.

FIG. 5 is a schematic sectional view of the present invention, illustrating the piston of the pressure cylinder reached its lower limit position.

DETAILED DESCRIPTION OF THE INVENTION

Referring to FIGS. 3-5, a pressure cylinder 20 in accordance with the present invention is shown comprising a first cylinder body 30, a second cylinder body 40, a piston 50 and a piston rod 60.

The first cylinder body 30 accommodates the piston 50 that divides the inside space of the first cylinder body 30 into a first chamber 31 and a second chamber 32. By means of an electromagnetic valve 70 to controls compressed air in and out of the first chamber 31 and the second chamber 32 through two air passages 71;72 respectively, the piston 50 is moved in direction toward the first chamber 31 or the second chamber 32.

The second cylinder body 40 defines a first passage 41 vertically connected to the first cylinder body 30, an oil storage chamber 42 vertically connected to the first passage 41, a second passage 43 vertically connected to the oil storage chamber 42 and a pressure chamber 44 vertically connected to the second passage 43. The oil storage chamber 42 has a cross-sectional area larger than the cross-sectional area of the pressure chamber 44. Further, two seal members 412 are mounted around the first passage 41. The second cylinder body 40 further defines therein in transverse (radial) direction an oil-storage passage 46 and an oil-output passage 47 respectively connecting the oil storage chamber 42 and the pressure chamber 44 to the outside of the pressure cylinder 20. Further, the oil-storage passage 46 is provided with a seal member 461 and a visual inspection window 462 to block its inside from the outside. The seal member 461 has a threaded portion threaded into the oil-storage passage 46 of the second cylinder body 40. The oil-output passage 47 is adapted for receiving a connector of piping (not shown) of an external device to be driven.

Further, the oil storage chamber 42 and oil-storage passage 46 of the second cylinder body 40 are formed in an integral part of the second cylinder body 40; the oil storage chamber 42 and second passage 43 of the second cylinder body 40 are formed in an integral part of the second cylinder body. Further, the bottom side of the oil storage chamber 42 of the second cylinder body 40 is made in the form of a tapered hole gradually reducing in diameter in direction toward the second passage 43. The second cylinder body 40 further defines a bottom chamber 48 that is kept in communication with the pressure chamber 44 and disposed at a farther location in axial direction relative to the oil-output passage 47 to enhance the effects of buffering.

The piston rod 60 is inserted through the first passage 41 of the second cylinder body 40 and tightly mounted with the seal members 412 to prohibit communication between the first cylinder body 30 and the second cylinder body 40. The piston rod 60 has a first end 61 connected to the piston 50, and a second end 62 suspending in the second cylinder body 40. Thus, the piston rod 60 can be driven by the piston 50 to move its second end 62 longitudinally and linearly in the second cylinder body 40.

Further, the electromagnetic valve 70 controls a compressed air in and out of the first cylinder body 30. The air passage 72 is kept in communication between the second chamber 32 of the first cylinder body 30 and the second cylinder body 40 at the same elevation relative to the oil-storage passage 46 that is kept in communication with the oil storage chamber 42. Thus, the internal space of the second cylinder body 40 is fully utilized, saving the consumption of materials.

When using the pressure cylinder 20, the second cylinder body 40 is used for storing a certain amount of a hydraulic oil in the oil storage chamber 42, enabling the second passage 43 and the pressure chamber 44 to be fully filled up with the hydraulic oil. As illustrated in FIG. 3, when the piston 50 is moved to its upper limit position, the second end 62 of the piston rod 60 reaches a first position P1 in the oil storage chamber 42, and the internal space of the oil storage chamber 42 is not fully occupied by the hydraulic oil. At this time, the electromagnetic valve 70 is controlled to increase the air pressure in the first chamber 31 of the first cylinder body 30, moving the piston 50 in direction toward the second chamber 32 and forcing the piston rod 60 toward the pressure chamber 44. During this stage, the piston rod 60 is forced into abutment with the second passage 43 tightly at the first time to interrupt communication between the pressure chamber 44 and the oil storage chamber 42 (see FIG. 4). Thereafter, the piston rod 60 increases the pressure to the hydraulic oil in the pressure chamber 44, forcing the compressed hydraulic oil out of the pressure chamber 44 through the oil-output passage 47, and the applied pressure will be stopped when the piston 50 reaches the lower limit position where the second end 62 of the piston rod 60 reaches a second position P2 in the pressure chamber 44 (see FIG. 5).

The pressure cylinder 20 is normally controlled to make a reciprocating motion, i.e., the oil-output passage 47 continuously and intermittently outputs the compressed hydraulic oil. Therefore, when the piston 50 is returned to its upper limit position subject to the control of the electromagnetic valve 70 and the second end 62 of the piston 60 is returned to the first position P1, the hydraulic oil will flow backwardly from the oil-output passage 47 to the second cylinder body 40 for a next output cycle. During the operation of the pressure cylinder 20, the hydraulic oil in the oil storage chamber 42 is supplied to the pressure chamber 44 of the second cylinder body 40 to make up any hydraulic oil loss. Thus, no any spare oil tank is necessary to refill the pressure chamber 44 with the necessary hydraulic oil. Thus, when compared to the conventional pressure cylinder design of the same capacity, the pressure cylinder has a relatively smaller size and weight. Further, because the oil storage chamber 42 is closely abutted to the second passage 43, the hydraulic oil can flow directly and downwardly out of the oil storage chamber 42 to fill up the second passage 43 and the pressure chamber 44 at a high speed subject to the effect of gravitational attraction, avoiding insufficient oil output. Further, the user can visually check the elevation of the fluid level of the hydraulic oil in the oil storage chamber 42 through the visual inspection window 452 at the oil-storage passage 46 so that a new supply of the hydraulic oil can be immediately provided to the second cylinder body 40 when the storage amount of the hydraulic oil in the oil storage chamber 42 is insufficient.

It is to be understood that, except the use of a compressed air in the first cylinder body 30 to move the piston 50, a hydraulic oil or any other power transfer means can be used as a substitute for moving the piston 50.

Although a particular embodiment of the invention has been described in detail for purposes of illustration, various modifications and enhancements may be made without departing from the spirit and scope of the invention. Accordingly, the invention is not to be limited except as by the appended claims. 

1. A pressure cylinder, comprising: a first cylinder body having accommodated therein a piston; a second cylinder body defining therein a first passage vertically connected to said first cylinder body, an oil storage chamber vertically connected to said first passage, a second passage vertically connected to said oil storage chamber and a pressure chamber vertically connected to said second passage, said oil storage chamber having a cross-sectional area larger than the cross-sectional area of said pressure chamber; and a piston rod inserted through said first passage of said second cylinder body in an airtight manner, said piston rod having a first end connected to said piston and a second end suspending in said second cylinder body, said piston rod being movable by said piston to move said second end between a first position in said oil storage chamber and a second position in said pressure chamber.
 2. The pressure cylinder as claimed in claim 1, wherein said second cylinder body further defines an oil-storage passage kept in communication between said oil storage chamber and the outside of the pressure cylinder, said oil-storage passage being covered with a visual inspection window.
 3. The pressure cylinder as claimed in claim 2, wherein said oil-storage passage of said second cylinder body is sealed with a threaded seal member.
 4. The pressure cylinder as claimed in claim 2, wherein said second cylinder body further defines a tapered hole located on a bottom side thereof and gradually reducing in diameter in direction toward said second passage.
 5. The pressure cylinder as claimed in claim 4, wherein said oil storage chamber and said oil-storage passage of said second cylinder body are formed in an integral part of the second cylinder body.
 6. The pressure cylinder as claimed in claim 5, wherein said oil storage chamber and said first passage of said second cylinder body are formed in an integral part of the second cylinder body.
 7. The pressure cylinder as claimed in claim 4, wherein said oil storage chamber and said first passage of said second cylinder body are formed in an integral part of the second cylinder body.
 8. The pressure cylinder as claimed in claim 2, wherein said oil storage chamber and said oil-storage passage of said second cylinder body are formed in an integral part of the second cylinder body.
 9. The pressure cylinder as claimed in claim 8, wherein said oil storage chamber and said first passage of said second cylinder body are formed in an integral part of the second cylinder body.
 10. The pressure cylinder as claimed in claim 2, wherein said oil storage chamber and said first passage of said second cylinder body are formed in an integral part of the second cylinder body.
 11. The pressure cylinder as claimed in claim 2, further comprising an air passage connected between said first chamber and said second chamber at an elevation equal to the elevation of said oil-storage passage relative to said oil storage chamber, and an electromagnetic valve adapted for controlling a compressed air in and out of said air passage.
 12. The pressure cylinder as claimed in claim 1, wherein said oil storage chamber and said first passage of said second cylinder body are formed in an integral part of the second cylinder body.
 13. The pressure cylinder as claimed in claim 1, wherein said oil storage chamber and said second passage of said second cylinder body are formed in an integral part of the second cylinder body.
 14. The pressure cylinder as claimed in claim 1, wherein said second cylinder body further defines a tapered hole located on a bottom side thereof and gradually reducing in diameter in direction toward said second passage.
 15. The pressure cylinder as claimed in claim 14, wherein said oil storage chamber and said oil-storage passage of said second cylinder body are formed in an integral part of the second cylinder body.
 16. The pressure cylinder as claimed in claim 15, wherein said oil storage chamber and said first passage of said second cylinder body are formed in an integral part of the second cylinder body.
 17. The pressure cylinder as claimed in claim 14, wherein said oil storage chamber and said first passage of said second cylinder body are formed in an integral part of the second cylinder body.
 18. The pressure cylinder as claimed in claim 1, wherein said second cylinder body further defines an oil output passage extending from said pressure chamber to the outside of said second cylinder body.
 19. The pressure cylinder as claimed in claim 18, wherein said second cylinder body further defines a bottom chamber kept in communication with said pressure chamber and disposed at a farther location in axial direction relative to said oil-output passage. 